Hip nail



R. G. TRONZO HIP NAIL Filed Jan. 16, 1961 INVENTOR 2 ymand 6. i'zqnza 3,076,453 HEP NAIL -:1 Raymond G. Tronzo, 522 Twin Galas Drive,

Wynnewood, Pa. Filed Jan. 16, 196i, Ser'. No. 82,765 8 Claims. Cl. 128 5 2) The present invention relates to a hip nail of the type which is used for internal metallic fixation of a femoral -neck fracture of a human hip or a similar fracture in vet erinary medicine.

A purpose of the invention is to reduce the tendency of ahip nail to back out of the head after being driven into the hip bone thereby. permitting separation of the. shaft and the head of the hip bone.

A further purpose is to reduce the tendency of the shaft of the bone to rotate relative to the head of the bone after internal metallic fixation .of the shaft. with respect to the head.

.A furtherpurpose is to prevent the necessity for fur- :ther impacting of the shaftfragment into the-head of the ,hip bone.

A further purpose is to continuously tension the nail by spring means "acting against aguiding portion of a side plate, said guiding portion serving to guide a nail extension.

Further purposes appear in the specification and in the claims.

Internal metallic fixation by the use of a hip nail is ac- .ceptedpract-ice in orthopedicsurgeryto iixa transverse fracture of. a hip in human. beings andis equally applicable to veterinary medicine. involving the higher animals. One method is called closed pinning of the fracture. Theusual practice is tomake an incision which exposes the end-of the shaft of the hip bone, and after properly positioning theshaft with respect to, the head of the bone,

to insert one or a plurality of guide-pins which can be examinedunder the .X-rayfiuoroscope to determine correct location. Once a guidepin has been properly inserted, ahole is usuallydrilled around the pin through ally aligned the fragments.

Although various other devices are used, a widely used hip nail is the Smith-Peterson nail whichhas three uniform radial flutes and is provided with a threaded socket to connect to the driving means, as well known. The flutes are substantially ofthe diameter of the base of the nail.

The Smith-Peterson nail and other similardevices have caused difliculty in service, particularly along thefollowing lines:

(1) There is a tendency for the. nail which-is inserted through the relatively soft interiorbone structure to back This has permitted separacationof thebreak in the neck ofthe bone. This tends to permit the head to wobble or oscillate, and does not secure the broken portions of the bone in close proximity where mending of the break is promoted.

(2) There is a tendency for the shaft to rotate with respect to the head, because of insuflicient anchorage of the rearward portion of the nail in theshaft of the bone.

(3) .Each pf these conditions .is likely to cause the with the shaft of the bone.

orthopedic surgeon to make a new incision and reinsert the nail with consequent discomfort to the patient and delay in recovery.

The present invention relates to an improved hipnail for insertion into transverse fractures ofthe hip bone and for an optional compression plate unit designed specifically for this nail device.

In accordance with the inventiomthe nail tends to produce axial components which holdthe head firmly against the shaft, thus avoiding the likelihood of separation at the point of break after the nail has been inserted.

. Furthermore, in accordance with the invention, the nail is firmly held with respect to the shaft so that rotation of the head with respect to the shaft is not possible.

In the nail of the invention, there are a plurality, suitably three or four equally circumferentially spaced straight radial flutes which run from end to end of the nail.

Thefiutes are wedge-shaped in axial cross section, tapering from a larger diameter near the base to a smaller diameter near the forward end or point of the nail. This tapering tends to promote a forward component on the shaft of the bone which holds the shaft of the bone tightly against the head at the point of the fracture.

"The flutes in cross section are similar to a knife blade.

At the forward end, the flutes have a plurality of socalled sharks teeth which slope gradaully in the forward direction and abruptly in the rearward direction so that they tend to prevent the nail from backing away from the head of the bone. This segment of the nail grips the bone similar to a broad-headed hunting arrow when drawn into an object.

In the preferred embodiment, these so-called sharks teeth where they join the flutes rearwardly thereof extend out further radially than the flutes so as to obtain a more firmgrip inthe bone.

Near the base of the nail in the preferred embodiment, the flutes extend out radially beyond the base so'that where a hole is drilled through the shaft of the bone at the diameter of the base, the flutes will tend to anchor firmly in the shaft as they cut their own path in the bone and prevent relative rotation of the shaft with respectto thehead of the bone.

As there may be a slight backing off of the nail, the portion of the flutes at the rearward end near the base are generally parallel to the axis, so that at this location, if the nail backs oif a slight distance the flutes will tend to engage the shaft of the bone firmly and will not permit the shaft to wobble with respect to the nail.

In the preferred embodiment of the invention, the base of the nail has an extension of the same diameter applied to it and this extension is guided on a side plate and spring urged outwardly to keep the head in firm engagement The hip nail of the invention is entirely. operative without using the side plate, but in a fracture where the physician feels that it is desirable to urge the head of the bone against the shaft, the side plate and the spring comprise a desirable additional feature.

In the drawings I have chosen to illustrate one only of the numerous embodiments of the invention, with a minor variation, choosing the form shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

FIGURE 1 is a diagrammatic axial section of a human hip bone and hip nail inserted therein according to the invention.

FIGURE 2 is a rear elevation of the hip nail taken from the position of the line 22 of FIGURE 1.

FIGURE 3 is a section on the line 3--3 of FIGURE 1. FIGURE 4 is a front elevation of the hip nail of the invention, taken in the position .of the line 4-4 "of FIGURE 1.

aura res 3 FIGURE 5 is a side elevation of a human hip bone having a hip nail of the invention inserted therein, and showing a compression plate unit specifically designed for use with this new nail. It can be used optionally for compression of the fracture fragments. FlGURE 5 is partly in axial section.

FEGURE 6 is a front elevation of the hip bone, inserted nail and compression plate unit of FIGURE 5.

Describing in illustration but not it: limitation and referring to the drawings:

The hip nail of the invention has a base 2%} which is suitably of circular exterior contour and is provided with a socket 21 which is internally threaded at 22 and adapted to receive a driving mechanism, a compression plate unit or other suitable equipment, as well known in the art.

Forward of the base the hip nail of the invention has a small central axial opening 23 which runs to the forward end or point 24 and is adapted to guide on a guide pin during insertion of the hip nail as previously described. The body 25 of the nail has a plurality, suitably three, equaily eircumferentially spaced straight radial flutes 26 which as shown best in FlGURE 1 have a tapered outer relatively sharp edge 27 from a point 23 near the forward end to a point 3%? near the rearward end. The outer edge '7 of the flute is suitably sharp and bladeshaped in cross section so that it will cut into and embed itself in the bone of the shaft 31.

in the preferred embodiment the flutes 26 at the rearward end extend out radially beyond the diameter of the base 2d, so that even where a. hole is drilled through the bone shaft 31 at the diameter of the base 20, the flutes will firmly anchor into the shaft and will avoid relative rotation of the shaft with respect to the hip nail. This outer extension beyond the diameter of the base leads to the creation of a shoulder at 3-2 where the flutes join the base.

At the forward end between the point 23 and the tip 24 of the nail, the flutes have a series of radially extending sharlrs teeth 33 as best seen in FIGURE 1, each of which has a rather gradually sloping forward portion 34 with respect to the axis (suitably at an angle to the axis of 5 to 60) and an abruptly sloping rearward portion 35 (suitably at an angle to the axis of 60 to 120) which is in the preferred embodiment substantially at right angles to the axis. Thus, though the sharks teeth enter the head 35 of the hip bone rather readily when the nail is driven into position, they tend to anchor firmly, and combined with the overall taper of the flutes exert an axial force which tends to hold the neck fracture point 37 of the hip bone close together to promote knitting.

The individual sharlrs teeth themselves taper so that the forward ones are at smaller maximum diameter than the rearward ones. At the rearward end at 28 where the sharxs teeth join the flute portion having the straight outer edge 27, the last sharks teeth preferably protrude out slightly beyond the rearward adjoining portion of the flutes so as to give improved anchorage in the bone.

Near the rearward end, the flutes suitably are parallel to the axis at their outer edges at 35, as best seen in FIGURE 1, so that if there is any tendency of the hip nail to back off slightly, the flute at 33 will still engage the bone and prevent relative rotation.

While the hip nail may be used without other equipment, it will optionally be employed with a compression plate unit as illustrated, comprising a circular extension 40 of the same outside diameter as the nail base threaded into socket 21, side plate 41 surrounding and guiding the extension at 42 and anchored into the shaft by fastening means such as screws 43, a helical compression spring 44 around the extension beyond the plate 41, and a suitably self-locking nut and washer 45 on the rearward threaded end of the extension. The hole in the plate at 42 is slightly larger than the diameter of the extension it! so as to allow the nail unit to be urged outwardly,

thus causing the head fragment to be held against the shaft 4. fragment by a compression force equal to the tension on the spring 44. T he extension fits like a rod in a hearing at to per it easy sliding of the nail. The angle of the side plate is adjusted by the surgeon depending on its angle of insertion. He makes this adjustment by well known bending irons.

in operation the hip nail will be inserted in the manner previously employed in inserting the Smith-ieterson nail. However, the first insertion will tend to hold the head and the shaft of the bone together more effectively than in the prior practice, due to the cooperative effect of the tapering flutes, and the S1 arlts teeth, and preferably also the extension of the flutes out beyond the base, and preferably also the parallel portions on the rear ends of the flute.

Tests have been made of the device of the invention, and it has been found that the hip nail functions as indicated and can be observed under X-ray to correctly hold the fractured areas and correctly position the head and the shaft.

In view of my invention and disclosure, variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore, claim all such insofar as they fall within the reasonable spirit and scope of my claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A hollow hip nail for joining together the shaft and the head of a hip bone, comprising a base adapted to be driven into the bone, at least three straight radial flutes extending out from the nail between the base and the forward end of the nail, tapering from a maximum radial extension near the base to a minimum radial extension near the forward end, and having near the forward end a plurality of radially extending teeth which slope gradually in the forward direction and abruptly in the rearward direction, terminating in a point at the forward end, said nail having an opening extending straight through the interior from one end to the other.

2. A hip nail of claim 1, in which the flutes at the rearward end extend radially beyond the diameter of the base.

3. A hip nail of claim 1, in which the flutes near the rearward end have sides parallel to the axis.

4. A hip nail of claim 1, in which said teeth extend out radially beyond the flutes rearward of the teeth at the point where said teeth terminate at the rearward end.

5. A hip nail of claim 1, in combination with an extension at the base of the nail Wholly outside the hip bone, means for securing the extension to the nail, a side plate adapted to be secured to the shaft wholly outside the hip bone and surrounding and guiding the extension and spring means acting against the side plate and urging the extension in the direction toward withdrawing the nail.

6. A hip nail of claim 1, in which the flutes at the rearward end extend radially beyond the diameter of the base, an extension secured to the base of the nail wholly outside the hip bone, a side plate adapted to be secured to the shaft Wholly outside the hip bone surrounding the extension and spring means acting from the side plate and urging the nail in the direction of withdrawal from the bone.

7. A hip nail of claim 1, in which the flutes near the rearward end have sides parallel to the axis, in combination with an extension secured to the base of the nail wholly outside the hip bone, a side plate adapted to be secured to the shaft wholly outside the hip bone surrounding and guiding the extension and spring means acting from the side plate and urging the nail toward withdrawal.

8. A hip nail of claim 1, in which said teeth extend out radially beyond the flutes rearward of the teeth at the .point where said teeth terminate at the rearward end, in

combination with an extension secured to the base of the nail wholly outside the hip bone, a side plata adapted to 8,076,453 5 6 be secured to the shaft wholly outside the hip bone and FOREIGN PATENTS surrounding the extension, and spring means acting from i the side plate and urging the extension in the direction of 735628 Great Bmam 1955 OTHER REFERENCES withdrawal of the nail.

References Cited in the file of this patent l ;1 Mississippi Docttg October 1949 (only page 3 UNITED STATES PATENTS m (Cm 942,668 Smith Dec. 7, 1909 

1. A HOLLOW HIP NAIL FOR JOINING TOGETHER THE SHAFT AND THE HEAD OF A HIP BONE, COMPRISING A BASE ADAPTED TO BE DRIVEN INTO THE BONE, AT LEAST THREE STRAIGHT RADIAL FLUTES EXTENDING OUT FROM THE NAIL BETWEEN THE BASE AND THE FORWARD END OF THE NAIL, TAPERING FROM A MAXIMUM RADIAL EXTENSION NEAR THE BASE TO A MINIMUM RADIAL EXTENSION NEAR THE FORWARD END, AND HAVING NEAR THE FORWARD END A PLURALITY OF RADIALLY EXTENDING TEETH WHICH SLOPE GRADUALLY IN THE FORWARD DIRECTION AND ABRUPTLY IN THE REARWARD DIRECTION, TERMINATING IN A POINT AT THE FORWARD END, SAID NAIL HAVING AN OPENING EXTENDING STRAIGHT THROUGH THE INTERIOR FROM ONE END TO THE OTHER. 